PROJECT SUMMARY Stroke is a leading cause of disability both in the United States and globally. Limited arm and hand function after a stroke can be a major challenge to a survivor?s independence and return to a healthy life. In addition to weakness, increased tone and spasticity are major causes of impaired arm function after stroke, with around 40% of survivors affected. There are very few effective treatments for tone and spasticity. A promising treatment to reduce tone and spasticity after stroke is vibrotactile stimulation (VTS). There is encouraging preliminary data from my prior research as well as others? indicating that VTS improves tone and spasticity. My pilot study with VTS of the phalanx using a glove-based system in 14 stroke patients with spasticity has shown significant reductions in spasticity over 8 weeks. The exact mechanisms underlying recovery after using VTS are unknown, but it is believed that sensory feedback modulates abnormal muscle activity. Key limitations to the use of VTS for treatment of spasticity post-stroke are: (1) there is limited understanding of the mechanisms underlying recovery from stimulation, which is needed to inform selection of VTS parameters to optimize recovery, and (2) there are no mobile devices available to administer and study this method of therapy for prolonged periods in the patient's home environment. A wearable VTS device could provide intensive, mobile, noninvasive stimulation. The purpose of this F32 postdoctoral fellowship is to inform the design of a wearable VTS system for the reduction of tone and spasticity after stroke. This will be achieved through three aims: Aim 1 ? Characterize the influence of cutaneous and proprioceptive vibratory phalanx stimulation on muscle activity and reciprocal inhibition in healthy people. Aim 2 ? Develop design guidelines for a wearable device that is accessible to users with spasticity. Aim 3 ? Determine the influence of VTS location on tone and spasticity in stroke patients. Together, these aims will help elucidate mechanisms underlying VTS for spasticity relief, and inform the development of a wearable device that may help improve recovery after stroke. The Fellow, who specializes in Wearable Computing and haptics, along with mentors Dr. Allison Okamura (Mechanical Engineering), Dr. Maarten Lansberg (Stroke/Neurology), and Dr. Kara Flavin (Physical Medicine and Rehabilitation) form an ideal team to execute this work. A training plan that includes clinical study design, work with patients, and interaction with other clinical investigators will give the Fellow a strong foundation for future technical innovation in health-related domains. Stanford University?s Stroke Clinic, Center for Design Research, and an ongoing clinical trial on the use of VTS to reduce spasticity, provide an excellent environment to perform this research.